SABC=1/2 AB*CK=1/2*18*12=108 SABC=1/2 AC*BH=1/2*27*BH 1/2 *27*BH=108 BH=108*2/27=8
1) (2p-q)²-(q+2p)²=(2p-q-q-2p)(2p-q+q+2p)=-2q*4p=-8pq
2) 4y²-(y+3)²=(2y-y-3)(2y+y+3)=(y-3)(3y+3)=3y²+3y-9y-9=3y²-6y-9
(1 1/9 * 0.27 - 3 1/3 * 0.15) - 1500 (-0.1)^3= (10/9 * 27/100 - 10/3 * 15/100) + 1500*0.001= (3/10 -5/10) +1.5= -0.2+1.5=1.3
Ответ на фото
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60-- 100%
z -- 60%
z=60*60/100=36 кг
60+x --100%
36+x --80%
(60+x)80=(36+x)100
(60+x)4=(36+x)5
240+4x=180+5x
240-180=5x-4x
60=x